Automatic telephone switching apparatus.



T. G. MARTiN.

AUTOM ATIC TELEPHONE SWITCHING APPARATUS.

APPLICATION FILE HEM/2,1911.

Patented Apr. 3,191?

HTTORNEYSN WITNESSES fi- T. a. MARTIN. I AUTQMATIC TELEPHONE SWITCHINGAPPARATUS APPLlCM'lON FILED MAY 2, I91!- Patented Apr. 3, 1917..

TALBOT e. MARTIN, or CHICAGO, ILLINoIs, AssIGNOa To AUTOMATIC nLEcTnIccoivi PANY, or oHIoAeO, ILLINoIs, A CORPORATION OF ILLINOIs.

AUTOMATIC TELEPHONE SWITCHING APPARATUS.

menses.

Specification of Letters Patent.

Patented Apr. atom.

. Application filed May 2, 1911. Serial No. 624,568.

To all whom it may concern:

Be it known that I, TALBOT G. MARTIN, a

have invented a certain new and useful Improvement in AutomaticTelephone Switching Apparatus, of which the following is aspecification.

My. invention relates to telephone systems in general, but moreparticularly to auto- .maticor semi-automatic telephone exchangesystems, and especially to systems of this trolling certain localcircuits.

kind inwhich the switches are controlled over the two sides of the linein series, or

operated by controlling the two sides of the line in series, asdistinguished from those systems in which the switches are controlled bygrounding the line.

group, and then motion in another direction to find a terminal in theselected group. As is well known, and in a common form of system, thefirst motion is vertical and the second rotary. Systems of this kind inwhich the switches are controlled over metallic circuits are'ordinarilyknown as twowire systems.

Prior to my invention two-wire systems of this character have beenprovided with auto matic switches, such, for example, as the well-knownfirst and second selectors, but in most cases these selectors wereprovided with the usual and well-known side switch. These side switcheswere in the nature of auxiliary switches for controlling the continuityof connection between the selectors and the trunks leading thereto, andfor con- Each side switch, in the well-known form of automatic switch ofthis character, was provided with three positions, whereby the selectorwas incapable of extending connection over a trunk line until after theside switch thereof had reached the third position. The arms or movablecontacts of the selector would engage with the terminals of the selected trunk line, but it was necessary for the side switch to then passfrom'second to third position in order to connect the said arms with thetrunk leading to the selector,

It also relates to a system of this kind in which said switcheshave-motion first in one direction tofind a and to thereby complete theconnection to the selected trunk line. These so-called side sw tches aresomewhat complicated, and in some ways are objectionable.

The object of my invention is, therefore, to provide a two-wireautomatic or semiautomatic telephone exchange system of the foregoinggeneral character in which automatic switches, such, for example, as thefirst and second selectors thereof, are constructed to operate withoutside switches, ordinary relays being substituted therefor, whereby theobjections to these side switches are eliminated, the work ordinarilyperformed thereby being taken care of by the said relays, which are, ofcourse, much more simple in form and construction.

To these and other useful ends my invention consists in mattershereinafter set forth and claimed.

In the accompanying drawings, Figures 1 and 2 show a complete connectionbetween a calling substation A (Fig. 1) and a called line (Fig. 2) in asystem embodying the principles of my invention. In Fig. 1 there isrepresented an automatic substation A to the line conductors of whichthere is allotted at the central oflice an individual or line switch C.At D there is shown amaster switch for Controlling a group of lineswitches C. The line switches of this group have common access to anumber of trunk lines which lead to first selector switches E. A numberof first selectors have common access to a number of second selectors F(Fig. 2), which in turn have access to connector switches H, by means ofwhich connection may be completed'with subscriber's lines. Associatedwith the connector H there are shown a ringing current generator M and abusy signaling apparatus L. 'At 13 a battery is shown having oneterminal grounded.

The substation A may be of any suitable common battery automatic type.As shown herein, .it comprises the usual receiver 25, switch hook 26,transmitter 27, ringer 29 and condenser 30. Being an automaticsubstation it is also provided with the impulse springs 31 and 32 and animpulse wheel 33. The impulse wheel 33 carries upon its pesite theterminals riphery the impulse teeth 34 and is secured to a shaft 35, towhich there is also attached a 'dial (not shown) provided with fingerholes, through the medium of which the impulse wheel may be rotated. Asthe impulse wheel is returned to normal position by a spring (not shown)after it has been rotated for any digit, each of the teeth 34 whichpasses the end 'of the spring 31 forces said spring out of engagementwith the spring 32. The number of times these springs are separateddepends upon the digit called.

The line switch C, which is individual to the line of substation A, andthe master switch D are modified forms of the general type of lineswitch and master switch disclosed in British Patent No. 26,301 of 1906,being of the partciular type shown in British Patent No. 1419 of 1910.As herein repre sented, the line switch C comprises, among otherdetails, a plunger (not shown) attached to the end of a so-calledplunger arm 39 which is controlled by the, magnet 40. The magnet 40 alsocontrols the relay armatures 41 and 42 and is composed of four windings,namely, a pull-in winding 43, a holding or cut-off winding 44, a linewinding 46 and an auxiliary winding 45. The core of the magnet isprovided near the center of its length with a lateral projection 47 bymeans of which the magnet is mounted upon the bracket 48, upon whichlatter the armatures 39, 41 and 42 are pivoted. With this method ofmounting the magnet the magnetic circuit of the windings43 and 44 ismaintained separate from that of the windings 45 and 46, so that thearmatures at one end of the magnet are not afiected by the energiza tionof the windings upon the other end of the magnet, only the winding 43being strong enough to attract the plunger arm39 from its normalposition. The winding 44 is not strong enough to thus operate theplunger arm, but will hold it in an operated position after it has beendrawn down'by the winding 43. When the plunger arm 39 is attracted bythe magnet 40, the plunger of the switch is forced into a bank ofcontact springs, forcing the springs 49, 51, 53 and 55 into engagementwith the springs 50, 52, 54 and 56, respectively. Although only one setof springs (49-56) is shown, each line switch C is provided with anumber of such groups of springs, each group forming the terminal of atrunk line leading to a selector E. Each trunk line is .multipledthrough the corresponding springs of all the line switches of the groupwhich is controlled by the master switch D.

The plungers of the line switches normally engage a so-called plungershaft (not shown) and, through the medium of the master switch D, arenormally maintained oppoof an idle trunk line. The master switch.consists essentially of a motor magnet 58 for rotating the ratchet wheel59. The ratchet wheel 59 is connected with the plunger shaft in such amanner that a rotary motion of the wheel imparts an oscillatory motionto the plunger shaft to move the plungers back and forth in front ofthetrunk terminals. To the plunger shaft there is also secured a lockingplate 62 provided near its outer edge with a number of openings adaptedto be engaged by the pin 64 upon the end of the armature 65. The holesin this plate are so spaced that the pin 64 can engage one of them andallow the armature to drop back only when the idle plungers are directlyopposite a trunk terminal. The master switch is also provided with abank of contacts comprising a common segment 60 and one individualsegment a for each trunk to which the switches C have access. The wiper61 always keeps the common segment in electrical connection with theindividual. contact of the trunk line before which the idle plungers areresting.

The selector E is of the general type of selector disclosed in UnitedStates Letters Patent No. 815,321, granted'to Keith, Erickson andErickson March 13, 1906, but has no side switch. Among other details,the selector E comprises a set of wipers 67, 68 and 69 carried upon avertically and rotatably movable shaft (not shown). The verticalmovement is controlled by the vertical magnet 70, and the rotarymovement is governed by the rotary magnet 71. The usual vertical androtary line relays are replaced by the doublewound line relay 7 7 whichis normally connected to the line through the springs of a cut-off relay76. Means for permitting the switch to be restored to normal positionare provided in the release magnet 78 which, upon energizing, withdrawsthe retaining pawls from the shaft. The springs 7 9 and 80 are permittedto close only when the switch shaft has been raised one or more stepsfrom its lowest position. The pairs of springs 7 2 and 7 3 are separatedby the armature of the rotary magnet just before it reaches the end ofthe stroke. The relays 82 and 83 are slow acting relays, (1., slow todeenergize after their circuits are broken. This slow action is usuallyaccomplished by placing a ring of copper around one end of the core ofthe relay magnet. The selector F is in all respects the same as theselector E.

The connector H is of the general type of connector switch disclosed inUnited States Letters Patent #815,17 6, granted March 13, 1906, toKeith, Erickson and Erickson, but, like the selectors, is modified inorder to operate 'in a two-wire system. Like the selectors, theconnector is provided with a shaft- (not shown) carrying the wipers 86.87 and' 'SS, and is controlled by the vertical magnet- 89 and rotarymagnet 90. The usual side switch is controlled by the private magnet 91in the usual manner. The connector is provided with a so-called backbridge relay 93 through which the called substation therewith. l

Having given a general description of the apparatus, I will now explainin detail the operations by which one subscriber establi'shes'connection with another in a system embodying the principles of myinvention.

It will be explained how substation A may obtain connection. with linenumber 2220. When the calling subscriber removes his receiverpreparatory to making a call, the switch hook rises, permitting thespring 95 to ,pass out of engagement with spring 97 and into contactwith spring 96, whereby the circuit ofthe ringer 29 and condenser 30 isbroken, and a bridge consisting of the substation transmitter andreceiver is closed across the line conductors 98 and 99. The closure ofthis bridge across the line completes an energizing circuit through theline 42, which operates to force the spring 105' into engagement withspring 101, whereby a circuit is closed through the pull-in winding 43.This circuit extends from ground G through springs 101 and 105, windings43 and 45, contact point 107 and armature 65 to batterylead 100. Thewinding 43, upon energizing, attracts the armature 41 and plunger arm39. The armature 41, upon being attracted, operates to disconnect theline winding 46 and ground G from the calling line.' The armature 42does not fall back immediately upon the deenergization of the winding46, but remains held up by current arm 39 forces spring 108 into contactwith flowing inthe winding 45 until the plunger spring 109, whereby thewinding 45 is shortcircuited and consequently deenergizes slowly to holdthe armature 42 in its operated positionfor an instant longer. Beforethe armature 42 is restored sufficiently to break the circuit of thewinding 43, a cir- 'cuit is closed through the winding 44 in thefollowing manner: When the springs 49- and 55 are forced into contactwith springs 50 and 56, respectively, by the plunger of the line switchC, a circuit is closedthrough the line relay 77 of the selector E. Thiscircuit extends from ground G through the lower winding of relay 77,springs 128 and 1 127, springs 56 and 55, thence over the heavyconductors .to and through substation A and back over the other side ofthe line,-and through the upper winding of the relay 77 to the batterylead 100. The relay 7 7, upon energizing, operates to close a circuitthrough the relay 82, said circuit extending from ground G through thesprings 110 and 111 and relay 82 to battery lead 100. The relay 82, uponenergizing, operates to close the circuit of the holding winding 44 ofthe line switch C, said circuit extending from ground G through thesprings113 and-114,

52 and 51 and winding 44 to battery lead 100. The current in thiswinding serves to hold the plunger arm 39 and armature 41 in theiroperated positions after the winding-43 has been deenergized. Theenergization of the relay 82 at the selector E also extends a guardingpotential from ground G over conductor 115 to the connector private bankcontacts of the calling line.

When the springs 53 and 54 are forced into contact by the plunger of theline switch, a circuit is closed through the master switch relay 116.This circuit extends from ground G through the springs 53 and 54,contact point 117, wiper 61, segment and relay 116 to battery lead 100.The relay 116, upon energi'zing, operates to close a circuit through therelay 66. The relay 66, upon energizing, operates to withdraw the pin 64from the plate62 and to close the circuit of the motor magnet 58. Thiscircuit extends from ground Gr through the magnet 58, interruptersprings 118, contact point 119 and armature to battery lead '100. Aslong as the armature 65 engages contact point 119, the magnet 58operates in a manner similar to that of a buzzer to rotate the ratchetwheel 59'step by step to advance the idle line switch plungers away fromthe trunk just seized. After the plungers have been advanceda shortdistance, the wiper 61 passes off the contact point 117 and allows therelays 116 and 66 to deenergize. The armature 65 does not fall backimmediately upon the dee'nergization of relay 66, but remains in contactwith contact point 119 until the next opening in the plate 62 passesunder the pin 64. When the next opening does pass under the pin 64 thearmature 65 falls back, forcing the pin into this opening to lock theplunger shaft and breaking the circuit'of the motor magnet 58. Theforegoing is the operation of the master switch in case the next trunkline after the one seized by the switch C is idle.

grounded, and consequently the relays 116 and 66 remain energized whilethe next opening is passing under the pin 64 and the plungers arecarried past the busy trunkto an idle one. As long as the master switch18 operating, the armature 65 is disengaged from the spring 107 and thespring 107 engages the spring 120, whereby the pull-1n wlndlngs of allthe idle line switches are disconnected from the battery and connected-to the busy signaling machine L. Vith this arrangement no'line switchcan be operated while its plunger is being moved from one trunk toanother, and any subscriber who attempts to make a call at that timew1ll receivethe busy signal, due to the inductive relation between theline winding momentarily. Each time the springs 31 and opposite ing,

32 are separated, the line relay 77 of the selector deenergizes. Sincethe relay 82 is slow acting it does not havetime to deenergize duringthe momentary interruption ofits circuit at the springs 110 and 111.Consequently, the engagement of the springs 110 and 112 closes anenergizing circuit through the vertical magnet 70. This circuit extendsfrom ground Gr through the springs 110 and 112, 121 and 122, 129 and130, relay 83 and-magnet 7 O to battery. The vertical magnet receivestwo impulses over this circuit and operates to raise the switch shaftand wipers two steps to a position the second row or level of bankcontacts. The relay 83 is energized in series with the vertical magnetbut, being slow acting, does not have time to deenergize betweenimpulses. The relay 83, upon energizclo'ses a circuit from ground Gthrough the springs 131 and 132 and the reenergizing,

lay 133 to battery. The relay 133, upon completes a locking circuit foritself; extending from ground Gr through the springs 113 and 114, 72,134 and 135 and the winding of said relay to battery. As a result of theclosure of this locking circuit, the relay 133 remains energized afterthe relay 83 denergizes. upon the completion of the impulses for thefirst digit 2." The relay 83, therefore, upon deenergizing, completes acircuit from ground Gr through the springs 113 and 114, 72, 134 and135-, 132 and 136, 73. and the rotary magnet 71 to battery. The rotarymagnet 71, upon energizing, rotates the wipers one step, and byseparating the springs 72 and 73 disconnects, the ground G* from themagnet 71 and the relay 133. If the first trunk line of the second levelis idle,'the relay 133 deenergizes as soonas the springs'7 2 areseparated. If this trunk is busy, however, the private wiper 69 findsthe contact which it engages The calling subgrounded ,and thereforeprevents the relay 133 from deenergizing. The magnet 71, however,deenergizes as soon as the'springs 7 3 are. separated, regardless ofwhether the relay 133 remains energized or not. If the relay 133 remainsenergized, the circuit of the rotary magnet is again closed as soon asits armature drops back far enough to permit the springs 72 and 7 3 toengage. Upon energizing the second time, the rotary magnet advances thewipers a second step. The rotary magnet continues to advance the wipersstep by step in this manner until the wiper 69 engages the non-groundedcontact of an idle trunk, whereupon the relay 133 deenergizes. \Vhen therelay 133 deenergizes, whether after one or several operations of therotary magnet, the separation of its springs 134 and 135 permanentlyopens the circuit of the rotary magnet to prevent its further operation.The deenergization of the relay 133 also completes a circuit from groundG6 through the springs 113 and 114, 72, 134 and 137 and 79 and the relay76 to battery. The'relay 7 6, upon energizing, disconnects the linerelay 77 from the line and extends the connection from the calling lineover the heavy conductors through the wipers 67 and 68 to the trunkconductors 13S and 139 which lead to the selector F (Fig. 2). iVhenthisoccurs the line relay 140 of the selector F becomes energized in thesame manner in which the relay 77 ot the selector E was first energized.The relay 140, upon energizing, closes a circuit from ground Gr throughthe springs- 141 and 142 and relay 143 to battery. The relay '143, uponenergizing, closes a circuit from ground Gr through the springs 144 and145, conductor 146, private wiper 69 of selector E, springs 134, 137 and79, and relay 76 to battery. This circuit maintains the relay 76energized after the ground G is disconnected by the relay 82, whichdeenergizes shortly after relay 77 is cut from the line. The relay 143of the selector F also extends a. guarding potential from ground G overthe conductor 146 to the private bank contacts of the trunk selected bythe selector E, to prevent the said trunk from seizure bv a secondswitch, and provides a holding circuit for the winding 44 of the 'lineswitch 0.

When the substation calling device is operated for the second digit, theselector F operates in the same manner as explained for the selector Eto extend the connection to the connector H. The line relay 147 of theconnector is energized as soon as connection is extended thereto andoperates to close a circuit through the relay 148. The relay 148, uponenergizing, supplies a new guarding potential for the trunks seized bythe selectors E and F, and a new holding circuit for the relays 149 and7 6 of the selectors E and F, and the winding 44. of the line switch C.This circuit extends from ground G through the springs 151 and 152,conductor 153 and private bank contacts of the trunk leading toconnector H to wiper 154. From the wiper 154 one branch of the circuitpasses through the springs 155 the relay 148 is slow-acting it does notdeenergize between impulses, and each time the'relay 147 deenergizes acircuit is closed from ground G through, the springs 158 and 159, 160and 161, vertical magnet 89, side switchwiper 162 and'relay 163 tobattery. The vertical magnet 89 is operated twice over this circuit toraise the shaft wipers two steps' The relay 163 is energized in serieswith the vertical magnet and closes a circuit from ground G through thesprings 164 and 165 and the private magnet 91 to the battery After thelast impulse is delivered to the vertical magnet, the slow acting relay163 deenergizes and opens the circuit of the private magnet. The privatemagnet, upon deenergizing, permits the side switch to pass from first tosecond position. When the substation calling device is-operated-for thelast digit 0, the line relay of the connector denergizes ten times eachtime closing a circuit from ground (ir through the springs 158 and 159,160 and 161 and 166, rotary magnet 90, side switch wiper 162 (in secondposition) and relay 163 to battery. The relay 163 operates in responseto this series of impulses in the same manner as for the previous series to cause the private magnet 91 to trip the side switch to thirdposition after the last impulse is delivered. The movement of the sideswitch wipers 168 and 169 to third position completes the connectionfrom the calling line througl'i the wipers 86 and 87 to the called lineto which the wipershave been rotated'by the ten steps ofthe rotarymagnet. It will be understood, of course, that the contacts 170, 171 and172 bear the same relation to the called line that the contacts 173, 174and 175 (Fig. 1) respectively, bear to the calling .line.. Theengagement of the side switclrwiper 176 with its thirdposition. contactpoint supplies a guarding potential from ground G through the springs177 .and 17 8 and private wiper 88 to the private bank contact 171 andthe corresponding contact in the banks of all the connectors which haveaccess to the .hne called. From the contact 171 a circuit extends overthe conductor 179 and through the cut-off winding of the line switch ofthe called line to battery. (See the contact 174 and wind mg 44 of thecalling line). The cut-off winding of the called line, upon energizing,attracts the cut-off armature, whichdisco'nnects the line switch fromtheline. The'engagement of the side switch wiper 162;:with its thirdposition contact point completes a circuit for the ringingrelay-180,.which circuit extends from ground G throughwth-e interrupter181, springs 188 and 189,, relay 180, side switch wiper 162, andrelay'163- to battery. The relay 180 is energizedintermittently overthis circuit bymeansof-theinterrupter 181 and operates to complete acircuit from one terminal of the generator M through the springs 182 and183, wipers 169 and 87, thence to and through the bells at the calledsubstation and back. over theother side of the line, and through wipers86 and 168 and springs 186 and 184-to the other terminal of thegenerator. When the called subscriber removes his receiver, his talkingcircuit is bridged across the line and, as soon thereafter asthe ringingrelay 180 detnergizes, the called telephonexisprovided with talkingcurrent over a circuit extending from ground G through the side switchwiper 176, lower winding of relay 93, springs 185 and 183,-wipers 169and 87, called telephone, wipers 86 and 168, springs 186 and 187 andupper winding of relay 93 v to battery. The relay 93, upon energizing,opens the circuit of the ringing relay at the springs 188 and189, andthe two connected subscribers may carryon an uninterrupted conversationover the circuit indicated by heavy conductors in the drawings.

After a conversation is completed the central oliice switches arereleasedvby the hanging up of the receiver at thecalling substation.When the relay 147 of the: connector denergizes, upon the hanging up ofthe receiver, it breaks the circuit of the r'ei lay 148. The relayl48,'upon de'energizing, closes a circuit from groundG through-thesprings 158 and 159-, 160 and magnet 191 and off-normal springs 192 to190, release battery. "When the magnet'191 energizesit 'withdrawstheretaining panels from the connector shaft and restores the sideswitch.

When the shaft reaches its lowest position it opens the circuit of themagnet 191.

The deenergiza'tion of the relay 14 the connector also breaksxtheholdinglcire cuits of the winding 1.4'of the line switch C and of relays7 6 and 149 of the selectors E and F. The winding 44, upon denergizring, permits the plunger of the line switch to be restored. Thedeenergization of the relay 7 6 closes a clrcuit from. ground G? throughsprings 110 and 112, 121 and'122= 129 and 193 and 80, and magnet 78 to'battery. withdraws the pawls from the shaft When The magnet D I-energizing,

the shaft reaches its lowest position it opens springs 79 and 80,allowing the magnet 78 to deenergizevv and disconnecting the relay 76from the spring 114: of the relay 82. The

switch F is released in the same manner by the deenergization of therelay 149.

If the called line had been busy when the connector H sought to makeconnection therewith, the connection would not have been completed andthe calling subscriber would have been given a busy signal. It thecalled line had been busy the private wiper 88 would have been standingon a grounded contact when the relay 163 deenergized after the lastdigit was called, and consequently the private magnet 91 would not havedeenergized to permit the side switch to pass to third position, butwould have been locked up over a circuit extending from the guardedprivate bank contact of the busy called line, over the wiper 88, springs17 8 and 17 7, lower winding of the relay 93, springs 185 and 183, sideswitch wiper 169 (in second position), springs 195 and 165 and magnet 91to battery. The relay 93 would have been energized over the circuit justtraced and aided in closing .a circuit from ground G through the springs16 1 and 196, 197 and 198, relay 199 and springs 200 and 201 to battery.The relay 199, upon energizing, would have shifted the holding groundfor the private magnet from the private wiper to ground G and the sideswitch would have remained locked in second position until the callingsubscriber hung up his receiver. The engagement of the springs 202 and203 of the relay 199 would have connected the busy signal machine L withthe calling line through the side switch wiper 168, ringer relay springs186 and 187 and condenser 204:. The return path for the busy signalcurrent would be from the calling line through the lower winding of theconnector line relay 1 17 to ground, thence through the battery B backto the machine L.

From the foregoing it will be seen that I provide a very simple andhighly eflicient two-wire system some of the switches of which are ofthe side switchless type. In other words, and notwithstanding that thesystem includes automatic switches which are controlled over the twosides of the line in series, no side switches are employed for theautomatic selectors, relays of a very simple form and construction beingused instead. One relay of 7 each selector is adapted by a singlemovement of its armature to connect the trunk with the line wipers ofmovable arms oi? the selector. As shown, the line wipers or movable armsof the first selector are normally disconnected from the trunk leadingto said selector. This is also true of the second selector, as thecontacts of the relay are normally open.

Furthermore, it will be seen that side switches are not necessary forcontrolling the local circuits of the switch. Relays are used for thispurpose as well, which relays are all in normal position during the timethat the selector is in use for talking purposes. In this way the localcircuit of the rotary magnet of the selector is in normal conditionwhile the selector is in operative position. In the old construction,however, the side switch remained in third position during conversationbetween the two subscribers, and did not return to normal position untilthe connection was released. Withmy improved arrangement, as stated, thelocal circuit of the rotary magnet, and the relay contacts controllingsaid circuit, are all in normal condition during the time that theselector is in operated positionthat is to say, during the time that itis in oil normal position to maintain the continuity of the talkingcircuit. Again, it will be seen that the operation of the rotary magnet,with my improved arrangement, is started bv the closing of normallyclosed contacts, which contacts are open during the vertical motion ofthe selector. Moreover, my in- Vention not only involves the use of onerelay for starting the operation of the rotary magnet, but also involvesthe use of another relay for stopping the operation of said magnet.Thus, as explained, nothing but simple relay contacts are employed forcontrolling the entire operation of the selector. In this waypractically the utmost simplicity of construction is insured, and theselectors are made reliable and serviceable in use.

What I claimas my inventionis:

1. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group, alinerelay for controlling the operation of said arms, an electromagnet, atrunk adapted by a single movement of the armature of said magnet to beconnected with said arms, means for controlling the two sides of saidtrunk in series to control said relay, a local circuit governing thesaid second motion, normally closed contacts in said local circuit,which contacts are open during the said first motion, and means wherebysaid contacts are then closed to start the second motion.

2. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group,an-electromagnet for producing the first motion, an electromagnet forgroups, the groups being disposed in parallel planes, movable armshaving motion in one direction to find a group and motion in anotherdirection to find a terminal in the selected group, electroinagnetmechanism for producing said first and second motions, a relay, a trunknormally disconnected from said arms, adapted by a single movement ofthe armature of said relay to be connected with said arms, means forcontrolling the two sides of said trunk in series to control said relay,a local circuit governing the said second motion, normally closedcontacts in said local circuit, which contacts are open during the saidfirst motion, and means whereby said contacts are then closed to startthe second motion.

4. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in-the selected group, a linerelay for controlling the operation of said arms, an electromagnet, atrunk adapted by a single movement of the armature of said magnet to beconnected with said arms, means for controlling thetwo sides of saidtrunk in series to control said relay, a local circuit governing thesaid second motion, contacts in said-local circuit, which contacts areopen during the said first motion, means whereby said contacts areautomatically closed upon the cessation of the first motion to start thesecond motion, other contacts in said local circuit, and means wherebysaid other contacts are automatically opened to stop said second motionwhen the said terminal is found.

5. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group, anelectroinagnet for producing'the first mot-ion, an ,electromagnet forproducing the second motion, a relay, a line adapted by a singlemovement of the armature of said relay tobe connected with said arms,means for controllingithe two sides of said line in series to controlone of said magnets, a local circuit governing the said sec- 0nd motion,contacts in said local circuit, which contacts are open during the saidfirst motion, means whereby said contacts are automatically closed uponthe cessation of the first motion to start the second motion, othercontacts in said local circuit, and

means whereby said other contacts are auto matically opened to stopsaid. second motion when the said terminal is found.

6. In a telephone system, an automatic" switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group,electromagnet mechanism for two sides of said trunk in series to controlsa1d relay, a local circuit governing the said second motion, contactsin said local circuit, which contacts are open during the said firstmotion, means whereby said contacts are antomatically closed upon thecessation of the first motion to start the second motion, other contactsin said local circuit, and means whereby said other contacts areautomatically opened to stop said second motion when the said terminalis found.

7. In a telephone system, an automatic 7 switch having bank terminalsdivided. into one direction to find a group and motion in anotherdirection to find a terminal in the selected group, a line relay forcontrolling the operation ofsaid arms, an electromagnet, a trunk adaptedby a single movement of the armature of said magnet, to be connected-with said arms, means for controlling the two sides of said trunkin series to con trol said relay, normally closed circuit 0on tacts inthe switch for starting the said sec- .100 groups, the groups beingdisposed in ,parallel planes, movable arms having motion in 0nd motion,which contacts are open during 7 the said first motion, and meanswhereby, said contacts are then automatically closed to start the'secondmotion.

8. In a telephone system, an automatic switch having bank terminalsdivided into,

groups, the groups being disposed in park.

allel planes, movable arms having motion in one direction to find agroup and motion in another direction to find a terminal 111 the.selected group, an electromagnet for producing the first motion, anelectromagnet for producing the second motion, a relay, a line adaptedby a single movement of the 1111111 ture of said relay to be connected.with said arms; means for controlling the two sides of said line inseries to control one of said mag-, nets, normally closed circuitcontacts in the producing said Ifirst and second motions, a-

switch for starting the said second motion, which contacts are openduring the said first motion, and means whereby said contacts are thenautomatically closed to start the second motion. I

9. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction tofind a terminal in the selected group,electromagnet mechanism for relay, a trunk normally disconnected fromsaid arms, adapted by a single movement of the armature of said relay tobe connected with said arms, means for controlling the two sides ofsaidtrunk in series to control said relay, normally closed circuit contactsin the switch for starting the said second motion, which contacts areopen during the said first motion, and means whereby said contacts arethen automatically closed to start the second motion.

10. In a telephone system, an automatic switch having bank terminalsdivided into groups, the grou s being disposed in parallel planes, movale arms having motion in one direction to find a group and motion inanother direction to find a terminal in the selected group, a line relayfor controlling the operation of said arms, an electromagnet, a trunkadapted by. a single movement of thearmature of said magnet to beconnected with said arms, means for controlling the two sides of saidtrunk in series to control said relay, circuit contacts in the switchfor starting the said second motion, other circuit contacts in theswitch, and means for opening said other contacts, when the saidterminal is found, to prevent further motion of the switch.

11. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group, anelectromagnet for producing the first motion, an electromagnet forproducing the second motion, a relay, a line adapted by a singlemovement of the armature of said relay to be connected with said arms,means for controlling the two sides of said line in series to controlone of said magnets, circuit contacts in the switch for starting thesaid second motion, other circuit contacts in the switch, and means foropening said other contacts, when the said terminal is found, to preventfurther motion of the switch. o

112. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group,electromagnet mechanism for producing said first and second motions, arelay, a trunk normally disconnected from said arms, adapted by a singlemovement of the armature of said relay to be connected with said arms,means for controlling the two sides of said trunk in series to controlsaid relay, circuit contacts in the switch for starting the said secondmotion, other circuit contacts in the switch, and means for opening saidother contacts, when the said terminal is found, to prevent furthermotion of the switch.

13. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group, a linerelay for controlling the operation of said arms, an electromagnet, atrunk adapted to be connected with said arms, means for controlling thetwo sides of said trunk in series to control said relay, a local circuitgoverning the said second motion, normally closed contacts in said localcircuit, which contacts are open during the said first motion, and meanswhereby said contacts are then closed to start the second motion.

14:. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group, anelectromagnet for producing the first motion, an electromagnet forproducing the second motion, a relay, a line adapted to be connectedwith said arms, means for controlling the two sides of said line inseries to control one of said magnets, a local circuit governing thesaid second motion, normally closed contacts in said local circuit,which contacts are open during the said first motion, and means wherebysaid contacts are then closed to start the second motion.

15. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group,electromagnet mechanism for producing said first and second motions, arelay, a trunk normally disconnected from said arms, adapted to beconnected with said arms, means for controlling the two sides of saidtrunk in series to control said relay, :1 local circuit governing thesaid second motion, normally closed contacts in said local circuit,which contacts are open during the mamas v said first motion, and meanswhereby said contacts are then closed to start the second motion.

16. In a telephone system, a vertical and i rotary motion switch, arelay in the switch for starting the rotary motion, another relay forstopping said rotary motion, a line, and ni'ea'ns for controlling thetwo sides of the line in 'series to control the switch.

175111 a telephone system, a vertical and rotary motion switch,electromagnet 'mechanism in the switch for producing said mo-' tion,relay mechanism in the switch for controlling said electromagnetmechanism, a line, and means for controlling the two sides of said linein series to control said relay mechanism, said electromagnet mechanismhaving a local circuit that is in. normal condition while the switch isin operated position. i

18. In a telephone system, a vertical and rotary motion switch having anoperating magnet the circuit of which is in normal condition while theswitch is in operated position, a line, and means for controlling thetwo sides of said line in series to control said switch.

19. In a telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction-to find a terminal in the selected group, a. linerelay for controlling for controlling the-two sides of said trunk inseries to, control said relay, a local circuit governing the said secondmotion, normally closed contacts in said local circuit, which contactsare open during the said first motion, means whereby said contacts arethen closed to start the second motion, a third arm, release mechanismfor said switch, and release circuits therefor including contacts ofsaid bank and said third arm.

20, In a. telephone system, an automatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group, anelectromagnet for producing the first motion, an electromagnet forproducing the second motion, a relay, a line,

means controlled by a simple movement of p the armature of said relay toconnect said line with said arms, means for controlling the two sides ofsaid line in series to control one of said magnets, a local circuitgovernin it i aid second motion, normally closed in said local circuit,which contacts during the said first motion, means are open magnet, a

whereby said contacts are then 'closedto start the second motion, athirdarm, release mechanism for said switch, and releasecir cuitstherefor including contactsof said bank and said third arm. T

21.'In a telephone system, an'autoinatic switch having bank terminalsdivided into groups, the groups being disposed in parallel planes,movable arms having motion in one direction to find a group and motionin another direction to find a terminal in the selected group,electromagnet mechanism for producing said first and second motions, arelay, a trunk normally disconnected. from said arms, means controlledby a single movement of the armature of saidrelay to connect said trunkwith said armsy'means for controlling the two sides of said'trunk inseries to control said relay, a local circuit governing the said second.motion, normally closed contacts in said local circuit, which contactsare open during the said first motion, means whereby saidcontacts arethen closed to start the second motion, a. third arm, release mechanismfor said switch, and release circuits therefor including contacts()ftSElld bank and said third arm.

22. In a telephone system, a switch having vertical and rotary motions,a line relay for controlling said switch, an operating magnetcontrolling the rotary motion of said switch, an energizing circuit forsaid magnet, a pair of relays controlling said energizing circuit, oneof said relays adapted to be energized in order to energize the secondofi said relays, and means for closing said energizing circuit for saidoperating'mag not by having said second relay energized while saidfirstrelay is deenergized.

23. In a telephone system, a vertical and rotary motion switch, avertical operating magnet, a rotary operating magnet, a slow actingrelay connected in series with said vertical operating magnet, a linerelay,

means for transmitting a plurality of impulses through said line relayto operate said vertical magnet to move said switch in avertical plane,a third relay having an energizing circuit controlled by said slowacting relay, means for locking said; third relay in position uponenergization, means for de'e'nergizing said slow acting relay after saidimpulses have been transmitted, and an energizing circuit for saidrotary operating magnet adapted to be closed upon the energization ofsaid third relay and the deenergization of said slow acting relay.

24. In a telephone system, a vertical and rotary motion switch, avertical operating rotary operating magnet, a slow acting relayconnected in series with said vertical operating magnet, line relay,means for transmitting a plurality 'of impulses through said line relayto operate said vertical magnet to movesaid switch in a vertical plane,a third relay having an energizing circuit controlled by said slowacting relay, means for locking said third relay in position uponenergiza- 'tion, means for deenergizing said slow act- 'lng relay after,said impulses have been transmitted, an energlzmg circuit for said 'forcontrolling said switch, an operating magnetcontrolling the'rotarymotion of said switch, an energizing circuit for said magnet, a pair ofrelays controlling said energizmg circuit, one of sa1d relays adapted tobe energized 1n order to energize the second of said relays, means forclosing said energizing circuit for said operating magnet by having saidsecond relay energized while said first relay is denergized, and meansfor controlling the operation of said switch over two sides of the linecircuit in series.

26. In a telephone system, a line, a switch, with a wiper havingvertical and rotary motion, a vertical operating magnet, a rotaryoperating magnet, a slow acting relay connected in series with saidvertical operating magnet, a second relay controlled by said sloW-acting relay, means for closing the energizing circuit for said rotaryoperating magnet by first energizing said relays and then deenergizingsaid slow acting relay, means for automatically interrupting the circuitof said rotary operating magnet, a switching relay for connecting saidline with said wiper, and means for controlling the operation of saidselector over two sides of the line circuit in series.

27. In a telephone system, a vertical and rotary motion switch, avertical operating magnet, a rotary operating magnet, a slow actingrelay connected in series with said vertical operating magnet, a linerelay,- means for transmitting a plurality of impulses through said linerelay to operate said vertical magnet to move said switch in a verticalplane, a third relay having an energizing circuit controlled by saidslow acting relay, means for locking said third relay in position uponenergizat'ion, means for deenergizing said slow acting relay after saidimpulses have been transmitted, an energizing circuit forsaid rotaryoperating magnet adapted to be closed upon the energization of saidthird relay and the deenergization of said slow acting relay, and meansfor controlling the operation of said switch over two sides of the linecircuit in series.

28. In a telephone system, a vertical and rotary motion switch, avertical operating magnet, a rotary operating magnet, a slow ctmg relayconnected in series with said vertical operating magnet, a line relay,.

means for transmitting a plurality of impulses through said line relayto operate said vertical magnet to move said switch in a vertical plane,a third relay having an energizing circuit controlled by said slowacting relay, means for locking said third relay in position uponenergization, means for deenergizing said slow acting relay after saidimpulses have been transmitted, an energizing circuit for said rotaryoperating magnet adapted to be closed upon the energization of saidthird relay and the deenergization'of said slow acting relay, means forautomatically interrupting the flow of current through said energizingcircuit for said rotary magnet, and means for controlling the operationof said switch over two sides of the line circuit in series.

29. In atelephone system, an automatic switch for use in establishing atalking circuit, a relay for controlling the connection of said switchwith the conductoraof said circuit, an energizing circuit for said relaynormally open at one point, means for closing said normally open contactpoint upon the initial movement of said switch, and means formaintaining said circuit open at a second point until said switch hascompleted its operation.

30. In a telephone system, an automatic switch for use in establishing atalking circuit, a relay for controlling the connection of said switchwith the conductors of said talking circuit, an energizing circuit forsaid relay including contacts normally maintained open while said switchis in normal position and adapted to be closed by the initial movementof said switch, normally closed contact points adapted to be opened uponsuch movement, and means for again closing said second-mcntioned contactpoints when said switch has completed its operation, whereby said relayis energized and said switch disconnected from the conductors of saidtalking circuit.

31. In a telephone system, an automatic switch for use in establishing atalking circuit, a relay controlling the connection of said switch withthe conductors of said circuit, an energizing circuit for said relayincluding normally open contacts adapted to be closed upon the firstmovement of said switch, a relay, means for operating said relay uponthe receipt of the first operating impulse to open said energizingcircuit at a second point, and means for maintaining said relayenergized until after said switch has completed its operation.

32. In a telephone system, an automatic switch for use in establishing atalking circuit, a relay for controlling the connection of said switchwith the conductors of said circuit, an energizing circuit for saidrelay normally open at one point, means for 010s talking circuit, anenergizing circuit for said relay including contacts normally maintained open while said switch is in normal position and adapted to beclosed by the initial movement of said switch, normally closed contactpoints adapted to be opened upon such movement, means for again closingsaid second-mentioned contact points when said switch has completed itsoperation, whereby said relay is energized and said switch disconnectedfrom the conductors of said talking circuit, and means for controllingthe operation of said switch over two sides of the line circuit inseries.

34:. In a telephone system, an automatic switch for use in establishinga talking circuit, a relay controlling the connection of said switchwith the conductors of said circuit, an energizing circuit for saidrelay ineluding normally open contacts adapted to be closed upon thefirst movement of said switch, a relay, means for operating said elayupon the receipt of the first operating impulse to open said energizingcircuit at a second point, means formaintaining. said relay energizeduntil after said switch has completed its operation, and means forcontrolling the operation of said switch over the two sides of the linecircuit in series.

35. In a telephone system, a line, a switch therefor having a wiper,lines provided with terminals accessible to said wiper, said terminalsdivided into groups, said switch provided with means for moving saidwiper to select a group of terminals and for advancing the wiper tolocate a terminal. in the elected group, said means including a relaywhich is energized when the group electing operation begins and whichdeenergizes to permit the operation that locates the terminal of theelected group, a switching relay for connecting the line with the wiperwhen the terminal is located, and a circuit for maintaining theswitching relay energized during talking.

36. In a telephone system, a line, a switch therefor having wipers,lines provided with terminals accessible to said wipers, said terminalsdiveded into groups, said switch provided with means for moving saidwiper to a particular one of said groups of terminals r in: i.- and foradvancing thefwipers to; ocatea, terminal in the particular group, saidneal s; including a relay which s energ zedavhenf the wipers areadvancedtof locatethe vpar; ticular'group and which deenergizes.totper;

mit the operation that locates,tlieter iiinal the particular group, aswitcli ngrelay for,

connecting the line with thewipers when the terminal is located, andacircuit ,for marine,

taining the switchingrelay energizepl diire,

ing talking. 37 In a telephone system, a line itch; therefor havingwipers,,li esprovided w ith terminals accessible tosaid jwipers, saidter;

minals divided into groups, s aid wit 1 p vided with a magnet formoving, saidi, perto a particular one of saidfgroups-of termi nals andprovided with a second i a'gnet yfor advancing the wipers to ,locate atermi ialc in the particular group, arela jwhi h energized when thewipers area'dvanced to locate the particular group and fwliicl xle;energizes to permit the operation thatlocates the terminal in theparticular groupyii" switching relay for connectingthe' line with,

the wipers when the terminal i lQcatechaiid a circuit for maintainingthe switching 'r'ela'y' energized during talking.

38. In a telephone system, a line, a switch therefor having wipers,lines provided with terminals accessible to said wipers, said terminalsdivided into groups, said switch provided with a motor magnet for movingsaid wipers to a particular one of said groups of terminals, andprovided with a second motor magnet for advancing the wipers to locate aterminal in the particular group, a relay which is energized when thewipers are advanced to locate the particular group and which deenergizesto permit the operation that locates the terminal in the particulargroup, a switching relay for connecting the line with the wipers whenthe terminal is located, and a circuit for maintaining the switchrelayenergized during talking.

, 89. In a telephone system, a line, a switch therefor having a wiper,lines provided with 40. In a telephone system, a line, a switch thereforhaving wipers, lines provided with terminals accessible to said wipers,said terminals divided into groups, said switch proand for advancing thewipers to locate a terminal in the partlcular group, said meansincluding a relay which is energized when the Wipers are advanced tolocate the par ticular group and which deenergizes to permit the.operation that locates the terminal in the particular group, a switchingrelay for connecting the line with the wipers when the terminal islocated, and means for maintaining said switching relay energized duringtalkin 41. In atelephone system, a line, a switch therefor havingwipers, lines provided with terminals accessible to said wipers, saidterfminals divided into groups, said switch provided with a magnet formoving said wipers to a particular one of said groups of terminals andprovided with a second magnet for advancing the wipers to locate aterminal in'the particular group, a relay which is energized when thewipers areadvanced to locate the particular group 'and which deenergizesto permit the operation that locates the terminals in the particulargroup, a switching relay for connecting the line with terminalsaccessible to said wipers, said terminals divided into groups, saidswitch provided wlth a motor magnet for moving said wipers .to aparticular one of said groups .of terminals, and provided with a secondmotor magnet for advancing the wipers to locate a terminal in theparticular group, a relay which is energized when the wipers areadvanced to locate the particular group and which deenergizes to permitthe operation that locates the terminal in the particular group, aswitching relay for connecting the line with the wipers when theterminal is located, and means for maintaining. said switching relayenergized during talking.

Signed by me at Chicago, Cook county Illinois, this 27th day of April,1911.

TALBOT G. MARTIN.

Witnesses:

ARTHUR J. RAY, E. D. Rims.

